Grab used for boring wells



Dec. 4, 1945. 'P, ALLARD 2,390,047

GRAB USED FOR BORING-WELLS Filed Feb. 1, 1943 Jill/en for against the walls or the bore-hole.

Patented Dec. 4, 1945 UNITED STATES PATENT OFFICE GRAB USED FOR BORING WELLS Pierre Jean-Marie Theodore Allard, Chantilly,

France; vested in the Alien Property dian Custo- Applicatlon February 1, 1943; SerialNO. 474,327 In France April 24, 1941 1 Claim.

The present invention relates to improvements in grabs used for boring wells and the like in order to improve the operation thereof.

In the use of such grabs of known type, it frequently happens that they become placed askew Owing to thisguiding device, it will be seen that the head of the grab can no longer come in the hole, resulting in risks of wedging and deviation of the bore-hole. Moreover, when such a grab operates with a single cable, its engaging and disengaging device becomes frequently clogged, either owing to the fact that the grab isplaced askew, or because when moving up or down its upper part scrapes the hole.

sponding to that of the scoops of the grab, and

arranged to guide the upper part of the grab substantially coaxially inside the bore-hole.

The other features and advantages of the invention are set forth in the following description with reference to the accompanying drawing which diagramatically illustrates by way of example and not in a limiting sense, an embodiment of the invention. In said drawing:

Fig. 1 is a side elevation of a grab constructed in accordance with the present invention, position within the bore-hole, and

Fig. 2 is a plan'view of the upper portion of the grab, on an enlarged scale.

In Fig. 1 will be seen a grab I comprising a suitable automatic engaging. and disengaging de-- vice I and scoops I, operating in the bore-hole 6.

The grab is provided adjacent its upper extremity with a guiding device constituted by shaped sheet metal plates 2 of rounded profile which are inscribed in the diameter D corre-' sponding to the diameter of the scoops of the grab, when open, and greater than the diameter oi the body of the grab proper.

The ribs 5 provided on the sheet metal plates 2 can be obtained by any means; they can be constituted by plates secured thereto which ofler the advantage that they can be replaced when they are worn by the nearly continual friction thereof in contact with said walls. On the other hand, the form of construction illustrated leaves, as shown in Fig. 2, very large passages between the grab body and the walls of the bore-hole, so that the device according to the invention does not brake the downward movement of the grab, even if the latter is to be lowered into a bore-hole full of water, which frequently happens. Preferably, as shown, the radial projections are separated from each other by wide intervals forming vertical passages. Finally, it is to be noted that during the raising or lowering of the grab, the latter can not become wedged nor rock, so that the head can in no case come in contact with the walls of the bore-hole and that the engaging and disengaging device 4. is consequently protected against shocks.

It is to be understood that the embodiment illustrated is not limiting and that it can be modi- -fled without departing from the scope of the presvertical position within the well, comprising I spaced guide members of flexible metal radiating into positions to contact the well wall at several points, said guide members being bowed and fastened at their ends to said body portion, and replaceable reinforcing ribs of sheet metal secured upon the intermediate portions of the said guide members in position to contact the well wall during descentand ascent of the grab device within the well.

PIERRE JEAN-MARIE THEODORE ALLARD. 

